Drilling-machine.



DRILLING MACHINE.

APPLICATION FILED SEPT. 17, 1903.

N0 MODEL.

2 SHEETS-SHEET i.

T WW:

WITNESSES: M INVENIOR TTORNEY No. 763,373. I I PATENTED JUNE 28, 1904. T. G. DAVIS. DRILLING MACHINE.

APPLICATION FILED SEPT. 17, 1903. i N0 MODEL. 2 SHEETS-SHEET 2.

UNITED STATES Patented June 28, 1904.

PATENT IFFICE. Y

DRILLING-MACHINE.

SPECIFICATION formingpart of Letters Patent No. 763,373, dated June 28, 1904.

Application filed September 17, 1903- Serial N 173,591. (No model.)

rock drills, and relates more particularly tomechanism for driving hand-operated drills. It is applicable to existing forms of drills and can be easily attached to the drill and quickly removed therefrom, besides being capable of being shifted into such a position that the drill may work close to the floor of the mine or close to the roof without interfering with the operation of the driving-cranks or their handles. Means is also provided for changing the speed and leverage of the drill.

The invention consists in the mechanism, its parts, and the combination of parts herein described and claimed, or the equivalent thereof, and is illustrated in the accompanying drawings, in which' Figure 1 is a side view of the driving-chain and its supporting-bracket. Fig. 2 is a top plan view of the same. Fig. 3 is a front elevation of a drill with my driving device attached, and Fig. 1 is a side view of the same. Fig. 5 is a perspective view of the reversible arm and the lower half of the spindle-bearing. Figs. 6 and 7 are part-sectional views taken on the line a: m of Fig. 5, illustrating the is thus formed on the hub 4 to take the reactionary thrust of the drill-spindle B.

The drill-spindle has a longitudinal key-seat B, and a key 5 is fixed in the bore of the sprocket-wheel 2 to engage the key-seat of the spindle, permitting the spindle to advance through the hub as the latter revolves.

Slidably mounted in a socket 6, formed in the lower part of the box 1, is the offset end 7 of an inclined bracket 7 The bracket carries at its outer end a revoluble crank-shaft 8. Upon this shaft is removably mounted a pair of sprockets 9 and 9. A sprocket-chain 9 connects one of these sprockets to the sprocket-wheel 2. The sprockets 9 and 9 are of different sizes and have central openings, so they can he slipped off the shaft 8, turned over and replaced, as is indicated in Figs. 6 and 7. By this arrangement either the small or large sprocket can be used, the smaller sprocket being employed for heavy work and slow drilling speed, and the larger sprocket being used for lighter work and higher speed.

To secure proper chain adjustment when the sprockets are changed, holes 7" are provided in the offset end of the bracket 7. .A pin 10 is dropped into the hole nearest the box 1 when the chain is sufficiently tight and engages the end of the bracket 1, fixing the distance between the sprockets.

The bent bracket 7 permits the cranks to be offset above or below the horizontal plane of the drill, as indicated by dotted lines in Fig. 3. This construction is of importance in drilling, for it permits the drill to be operated close to the floor or roof of the mine without danger of-bruising the workmans hands, as is frequently the case with the common forms of cranks connected direct to the drill-spindle.

By the means above described I have produced a simple, compact, and eflicient mechanism for driving drills that can be quickly shifted to admit of drilling close to floors,

roof, and walls and so arranged that its leverage or driving power can be quickly changed to suit the material to be drilled.

What I claim as my invention, and desire to secure by Letters Patent, is as follows:

1. In a drill-driving mechanism the combiable internally-tln'eaded box having a socket and a thrustbearing; of an inclined bracket having an offset end engaging said socket; means for adjusting the offset end of the bracket in the socket; a sprocket-Wheel having an annular grooved and centrally-bored hub mounted in said thrust-bearing; a key fixed in the bore of the hub to slidably engage the key-seat of the spindle; a crank-shaft at the outer end of the inclined bracket; sprocket- Wheels removably mounted on said crankshaft, and a driving-chain on said Wheels for the purposes set forth.

2. In a drill of the class described, the combination with the frame, the threaded drillspindle having a key-seat and the verticallymovablc, internally-threaded box to receive said spindle; of a thrust-bearing carried by said box; a sprocket-wheel having a centrallybored hub revolubly mounted on the thrustbcaring; a key fixed in the bore of the sprocket- Wheel hub to slidably engage the key-seat of the spindle; an inclined bracket having an offset end removably secured to said box; a crank shaft at the outer end of the inclined bracket; sprocket-wheels removably mounted on said crank-shaft and a driving-chain, all arranged for the purposes set forth.

3. In a drill of the class described the combination of a thrust-bearing carried by the spindle-box; a centrally-bored sprocket-Wheel revolubly mounted in said thrust bearing; means for positively rotating the drill-spindle With the sprocket-Wheel While permitting longitudinal movement of the spindle; an offset bracket reversibly secured to said box; sprocket\vl1eels carried by the outer portion of said bracket and means for rotating said sprocket-Wheels to operate the spindle.

1n testimony whereof I afiix my signature in presence of two Witnesses.

THOMAS G. DAVIS.

Witnesses:

A. H. Gross, F. \V. Dn F012. 

